In IOS, when we double tap the home button, it lift's the current app and shows all the app that are running on the bottom. I can scroll the bottom and select the music player option from there. I want to achieve the same screen lift effect, when user taps a button from withing the app instead of double tapping the home button. Is it possible to that? If yes, how can we do it?

It is not possible, primarily because it produces unexpected behavior in your app. The end user will get confused when such behavior is provided from within the app.
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SrikanthDec 24 '12 at 17:22

Are you asking how to invoke the app-switcher UI programmatically, or how to replicate the "screen lifting" visual effect? The former is not possible with public API; for the latter, some UIView animation should do the trick.
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ricksterDec 24 '12 at 18:35